Yesterday, the Prime Minister’s temper got the better of his judgement. It was a bad sign.

This is a pro-Brexit site, in case you hadn’t noticed. But it doesn’t follow that because this is so we, or anyone else, should lose objectivity and seek to claim that up is down and black is white. I agree with Boris Johnson’s view on leaving the EU, but understand why David Cameron is angry with him. In Boris’s own words, he has “never been an Outer”. His about-turn is not untinged by personal ambition. His grandstanding outside Downing Street last week was, let’s face it, ludicrous. And by all accounts he made his intentions known to the Prime Minister in a brusque and slapdash manner.

Cameron will have seethed and fizzed at the Mayor’s antics like a Vitamin C tablet chucked in a glass of tapwater – and I would feel much the same in his position. But his reckless assault on Boris in the Commons yesterday was a bad mistake and a baleful sign. A single emphatic reference to the double referendum issue would have made his point firmly but politely. To lay bare the Party’s tensions over his successor was to let that seething anger get the better of him.

It was also unfair. Yes, Boris and his aspirations always go together – quis separabit? – but there is more to his position than that: he knows and understands the EU well, and has pondered Britain’s relationship with it for a very long time. William Hague has rushed out in the Daily Telegraph this morning to urge calm on all sides. He will have written not out of decorousness, not even from duty, but from his perch as a historian. Like Nick Timothy on our site this morning, he understands how past fissures on the Corn Laws and tarrif reform cast the Conservatives out of office for a generation.

The Prime Minister presented himself yesterday almost as a neutral bystander – a man who stands above the fray, unsoiled by the scrummaging for the Tory succession. But there is as much at stake for his reputation as for everyone else’s. Boris wants to be Prime Minister. Cameron wants to win his third referendum. It will do his Party no good if he does so but it is left a wasteland afterwards. George Osborne will have been watching anxiously.